package com.su.tools;

import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.Properties;

import javax.xml.bind.PropertyException;

import org.apache.ibatis.executor.ErrorContext;
import org.apache.ibatis.executor.ExecutorException;
import org.apache.ibatis.executor.statement.BaseStatementHandler;
import org.apache.ibatis.executor.statement.RoutingStatementHandler;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.mapping.ParameterMode;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Plugin;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.property.PropertyTokenizer;
import org.apache.ibatis.scripting.xmltags.ForEachSqlNode;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.type.TypeHandler;
import org.apache.ibatis.type.TypeHandlerRegistry;

import com.su.util.ReflectHelper;
import com.su.util.Page;
/**
import com.entity.Page;
 
import com.util.Tools;
 * 
* 类名称：PagePlugin.java
* 类描述： 
* @author FH
* 作者单位： 
* 联系方式：qq313596790
* 创建时间：2014年7月1日
* @version 1.0
 */
@Intercepts({@Signature(type=StatementHandler.class,method="prepare",args={Connection.class})})
public class PagePlugin implements Interceptor {

	private static String dialect = "";	//数据库方言
	private static String pageSqlId = ""; //mapper.xml中需要拦截的ID(正则匹配)
	
	public Object intercept(Invocation ivk) throws Throwable {
		// TODO Auto-generated method stub
//		if(ivk.getTarget() instanceof RoutingStatementHandler){
//			RoutingStatementHandler statementHandler = (RoutingStatementHandler)ivk.getTarget();
//			BaseStatementHandler delegate = (BaseStatementHandler) ReflectHelper.getValueByFieldName(statementHandler, "delegate");
//			MappedStatement mappedStatement = (MappedStatement) ReflectHelper.getValueByFieldName(delegate, "mappedStatement");
//			
//			if(mappedStatement.getId().matches(pageSqlId)){ //拦截需要分页的SQL
//				BoundSql boundSql = delegate.getBoundSql();
//				Object parameterObject = boundSql.getParameterObject();//分页SQL<select>中parameterType属性对应的实体参数，即Mapper接口中执行分页方法的参数,该参数不得为空
//				if(parameterObject==null){
//					throw new NullPointerException("parameterObject尚未实例化！");
//				}else{
//					Connection connection = (Connection) ivk.getArgs()[0];
//					String sql = boundSql.getSql();
//					//String countSql = "select count(0) from (" + sql+ ") as tmp_count"; //记录统计
//					String countSql = "select count(0) from (" + sql+ ")  tmp_count"; //记录统计 == oracle 加 as 报错(SQL command not properly ended)
//					PreparedStatement countStmt = connection.prepareStatement(countSql);
//					BoundSql countBS = new BoundSql(mappedStatement.getConfiguration(),countSql,boundSql.getParameterMappings(),parameterObject);
//					setParameters(countStmt,mappedStatement,countBS,parameterObject);
//					ResultSet rs = countStmt.executeQuery();
//					int count = 0;
//					if (rs.next()) {
//						count = rs.getInt(1);
//					}
//					rs.close();
//					countStmt.close();
//					//System.out.println(count);
//					Page page = null;
//					if(parameterObject instanceof Page){	//参数就是Page实体
//						 page = (Page) parameterObject;
//						 page.setEntityOrField(true);	 
//						page.setTotalResult(count);
//					}else{	//参数为某个实体，该实体拥有Page属性
//						Field pageField = ReflectHelper.getFieldByFieldName(parameterObject,"page");
//						if(pageField!=null){
//							page = (Page) ReflectHelper.getValueByFieldName(parameterObject,"page");
//							if(page==null)
//								page = new Page();
//							page.setEntityOrField(false); 
//							page.setTotalResult(count);
//							ReflectHelper.setValueByFieldName(parameterObject,"page", page); //通过反射，对实体对象设置分页对象
//						}else{
//							throw new NoSuchFieldException(parameterObject.getClass().getName()+"不存在 page 属性！");
//						}
//					}
//					String pageSql = generatePageSql(sql,page);
//					ReflectHelper.setValueByFieldName(boundSql, "sql", pageSql); //将分页sql语句反射回BoundSql.
//				}
//			}
//		}
		return ivk.proceed();
	}

	
	/**
	 * 对SQL参数(?)设值,参考org.apache.ibatis.executor.parameter.DefaultParameterHandler
	 * @param ps
	 * @param mappedStatement
	 * @param boundSql
	 * @param parameterObject
	 * @throws SQLException
	 */
	private void setParameters(PreparedStatement ps,MappedStatement mappedStatement,BoundSql boundSql,Object parameterObject) throws SQLException {
//		ErrorContext.instance().activity("setting parameters").object(mappedStatement.getParameterMap().getId());
//		List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
//		if (parameterMappings != null) {
//			Configuration configuration = mappedStatement.getConfiguration();
//			TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();
//			MetaObject metaObject = parameterObject == null ? null: configuration.newMetaObject(parameterObject);
//			for (int i = 0; i < parameterMappings.size(); i++) {
//				ParameterMapping parameterMapping = parameterMappings.get(i);
//				if (parameterMapping.getMode() != ParameterMode.OUT) {
//					Object value;
//					String propertyName = parameterMapping.getProperty();
//					PropertyTokenizer prop = new PropertyTokenizer(propertyName);
//					if (parameterObject == null) {
//						value = null;
//					} else if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
//						value = parameterObject;
//					} else if (boundSql.hasAdditionalParameter(propertyName)) {
//						value = boundSql.getAdditionalParameter(propertyName);
//					} else if (propertyName.startsWith(ForEachSqlNode.ITEM_PREFIX)&& boundSql.hasAdditionalParameter(prop.getName())) {
//						value = boundSql.getAdditionalParameter(prop.getName());
//						if (value != null) {
//							value = configuration.newMetaObject(value).getValue(propertyName.substring(prop.getName().length()));
//						}
//					} else {
//						value = metaObject == null ? null : metaObject.getValue(propertyName);
//					}
//					TypeHandler typeHandler = parameterMapping.getTypeHandler();
//					if (typeHandler == null) {
//						throw new ExecutorException("There was no TypeHandler found for parameter "+ propertyName + " of statement "+ mappedStatement.getId());
//					}
//					typeHandler.setParameter(ps, i + 1, value, parameterMapping.getJdbcType());
//				}
//			}
//		}
	}
	
	/**
	 * 根据数据库方言，生成特定的分页sql
	 * @param sql
	 * @param page
	 * @return
	 */
	private String generatePageSql(String sql,Page page){
//		if(page!=null && Tools.notEmpty(dialect)){
//			StringBuffer pageSql = new StringBuffer();
//			if("mysql".equals(dialect)){
//				pageSql.append(sql);
//				pageSql.append(" limit "+page.getCurrentResult()+","+page.getShowCount());
//			}else if("oracle".equals(dialect)){
//				pageSql.append("select * from (select tmp_tb.*,ROWNUM row_id from (");
//				pageSql.append(sql);
//				//pageSql.append(") as tmp_tb where ROWNUM<=");
//				pageSql.append(") tmp_tb where ROWNUM<=");
//				pageSql.append(page.getCurrentResult()+page.getShowCount());
//				pageSql.append(") where row_id>");
//				pageSql.append(page.getCurrentResult());
//			}
//			return pageSql.toString();
//		}else{
			return sql;
//		}
	}
	
	public Object plugin(Object arg0) {
		// TODO Auto-generated method stub
		return Plugin.wrap(arg0, this);
	}

	public void setProperties(Properties p) {
//		dialect = p.getProperty("dialect");
//		if (Tools.isEmpty(dialect)) {
//			try {
//				throw new PropertyException("dialect property is not found!");
//			} catch (PropertyException e) {
//				// TODO Auto-generated catch block
//				e.printStackTrace();
//			}
//		}
//		pageSqlId = p.getProperty("pageSqlId");
//		if (Tools.isEmpty(pageSqlId)) {
//			try {
//				throw new PropertyException("pageSqlId property is not found!");
//			} catch (PropertyException e) {
//				// TODO Auto-generated catch block
//				e.printStackTrace();
//			}
//		}
	}



	
}
